Purdue News
Purdue News
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February 1998
Conservation tillage numbers plow conventional acres underWEST LAFAYETTE, Ind. -- Nationally, conservation tillage acres outstripped conventional acres for the first time ever last season, with 37.3 percent of the cropland planted in no-till, ridge till and mulch till systems compared to 36.5 percent conventionally tilled or plowed.
Indiana's conservation tillage acreage was up 680,000 acres, to 47.7 percent of all crop acreage. Conventionally tilled Hoosier acres accounted for 38.5 percent. Indiana's conservation tillage percentages have held fairly steady for the past three years. "We've been on a plateau since 1995," says Mark Evans, a conservation tillage expert with the state's T-by-2000 soil erosion education program. "A couple of cold, wet springs in a row had farmers out doing more cultivation in an attempt to warm the soil." Conservation tillage leaves at least 30 percent of the field covered with residue from previous crops after planting. These systems primarily include no-till and ridge-till, but some chisel plows and disk systems also leave 30 percent or higher residue levels. The corn stalks or wheat or soybean stubble help hold the soil in place and reduce erosion by 50 percent or more, says Evans, who works for a partnership between the Purdue University Department of Agronomy and the Indiana Department of Natural Resources that teaches conservation tillage. Soil quality also improves, because the residue returns nutrients to the crop and helps the soil retain water. Earthworms, an indicator of soil health, make a dramatic comeback when fields aren't plowed, Evans says. Conservation tillage also cuts down on tractor trips across the field, saving money and lessening the potential for soil compaction. No-till is the purest form of conservation tillage, where there is no mechanical soil preparation before planting. Other methods vary by the amount of soil disruption and remaining residue. The annual national survey is conducted on a county-by-county basis by U.S. Department of Agriculture Natural Resources Conservation Service and soil and water conservation districts and released by the Conservation Technology Information Center. The survey results indicate conservation tillage systems -- no-till, mulch-till, and ridge-till -- accounted for 109.8 million acres or 37 percent of the 294.6 million cropland acres planted in the United States in 1997. That puts conservation tillage systems ahead of conventional-till (plowed or intensively tilled) systems, which fell by 4 million acres to a total 107.6 million acres planted. A system called reduced-till accounts for the rest of the cropland (77.3 million acres) planted in 1997. An overview of the survey can be found at https://www.ctic.purdue.edu/Survey/Survey.html. The survey indicates that farmers in five states-- Iowa, Illinois, South Dakota, Kansas and Indiana-- contributed 5 million of the 6 million-acre increase in acres grown with conservation tillage systems. Farmers in Iowa adopted conservation tillage planting and management systems on more than 1.5 million additional cropland acres in 1997 to lead all other states, while producers in Illinois added more than 1 million acres. South Dakota, the leading gainer in 1996, added 800,000 more acres of conservation tillage in 1997. Kansas farmers almost matched that number with 790,000 new acres under conservation tillage in 1997. Indiana growers rebounded from a loss in such acreage in 1997 to post a 680,000-acre gain in 1997. Indiana has traditionally been a national no-till leader. In 1995 Indiana was the first state in the country to have more than half its soybean acres in no-till. In 1997 Indiana no-till soybeans stood at 51 percent with 2.6 million acres. No-till corn, though, has yet to catch on in Indiana, dropping from a high of 23 percent of corn acreage in 1993 to 17.3 percent, or 1.04 million acres, in 1997. "Corn doesn't like the cool, wet environment we've had in the spring and hasn't been as successful as soybeans," Evans says. "Planting variation and stand establishment have been problems for no-till corn growers as well." There are success stories in some areas of the state, such as Evans' home base of Putnam County. Farmers there planted 77 percent of the soybean acreage and 39 percent of corn fields in no-till. "Conservation tillage is almost a way of life there," Evans says. Soil erosion is more than just a soil productivity problem, Evans says. Sediment has been named the top contaminant of surface waters in Indiana and the nation, and agricultural runoff and soil erosion is coming under increasing scrutiny. DePauw University zoology Professor Emeritus Jim Gammon has been studying a 10-mile stretch of the Big Raccoon Creek in northern Putnam County since 1981, when he found the stream bereft of fish communities he had seen there 20 years before. He credits conservation tillage technology with contributing to their comeback. "There's been steady improvement into the '90s. The stream has come back," Gammon says. "The number of species has increased. Everything's back except for the smallmouth bass. "We've even seen a couple bass, and the recovery potential is there, too, if we have the right spawning conditions."
Sources: Mark Evans, (765) 653-9785; e-mail,
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